1. Technical Field
Various embodiments relate generally to an electronic device, and more particularly, to a semiconductor memory device including a three-dimensional array structure.
2. Related Art
Semiconductor memory devices are embodied with semiconductors such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), or indium phosphide (Inp). Semiconductor memory devices may be classified into in to two classes. One class may include volatile memory devices and the other class may include non-volatile memory devices.
Volatile memory devices lose stored data when the power is off. Examples of volatile memory devices include Static RAM (SRAM), Dynamic RAM (DRAM) and Synchronous DRAM (SDRAM). Non-volatile memory devices can retain stored data regardless of power on/off conditions. Examples of non-volatile memory include Read Only Memory (ROM), Mask ROM (MROM), Programmable ROM (PROM), Erasable Programmable ROM (EPROM), Electrically Erasable and Programmable ROM (EEPROM), flash memory, Phase-change Random Access Memory (PRAM), Magnetic RAM (MRAM), Resistive RAM (RRAM) and Ferroelectric RAM (FRAM). Flash memories may be classified into two types of memories. One type may include NOR-type memories and the other type may include NAND-type memories.
Recently, to improve the degree of integration in semiconductor memory devices, research has been conducted on semiconductor memory devices having a three-dimensional array structure.